What's the best MTB rim width?

Unravel the mystery that is rim widths and find out what's best for you.

Looking back over the many hours spent on each rim width it is hard to call out a so-called winner. As we were using the same setup with only the rim width changing from test to test we would have to say that overall the XM 481 was the best suited to the 27.5 x 2.4” tyre size we were used, and how we were riding. The large amount of support that the 30mm internal rim gives the tyre means that if desired you could perhaps move up to a 27.5 x 2.5” tyre for that extra grip with out any issues.

By no means are we saying this is the perfect width rim for any bike or any use. But it does come as no surprise that the stand out rim width of 30mm is what we are seeing as close to standard on most 150mm-160mm travel bikes sporting 2.4”-2.5” tyres in all wheel sizes. But next issue we’ll have a test of the DT Swiss XMC 1200 trail wheels that have a 29mm internal, and they are pretty much the same wheels that XC phenom Nino Schurter used in 2017 for such a dominant season, after extensive testing in 2016. So wider rims aren’t just the domain for longer travel bikes, but also aggressive riding no matter the discipline.

During the testing we were questioned as to why the XR 361 rim was included. With a 22mm internal volume, this model represents the internal volume that so many rims have been using until the past couple of years. So if your wheel set is a little older, chances are the internal rim width is somewhere around 22-23mm. And sure, you can fit wider tyres if you have the frame and fork clearance, but our results should show you why you just might not be getting the ride you expected by doing so. Similarly, the XM 421 with a 30mm external width is a great example of where many of the ‘30mm’ rims on the market sit. It’s a really popular size for modern XC bikes, and while it can suit a 2.4” tyre, they are probably best suited to 2.2-2.35” tyres.

With tyre sizes starting to increase and 2.6”-2.8” tyres popping up more and more we may need to revisit this story this time starting with a 40mm internal rim width. Wider tyres are better supported with wider rims, especially if you want to get the full performance advantages – so if you’re looking for that extra edge in performance from your bike, have a think about your rolling stock and pay attention to internal rim width and optimising your tyre pressures.